A phrase is restrictive (also called essential) if it narrows down the word it modifies. It tells which one of a noun you are writing about. A restrictive phrase is necessary to the meaning of the sentence. Restrictive phrases do not have commas around them.
The man wearing the white jacket is our coach. There are several men. Wearing the white jacket restricts which man is the coach. If we take the phrase out, we don't know who the coach is.
A phrase is nonrestrictive (also called nonessential) if we know exactly who or what is being written about without the phrase. A nonrestrictive phrase is simply adding extra information. Nonrestrictive phrases need commas around them.
Mr. Davis, wearing a white jacket, is our coach. We know Mr. Davis is the coach. We are adding that he is wearing a white jacket. If we take the phrase out, we still know that Mr. Davis is the coach.
Practice What You've Learned
Identify the bold-faced participial phrase as restrictive or nonrestrictive. Commas have been left out on purpose.
The car driving so slowly has a flat tire and is driving on its spare. restrictive/nonrestrictive
Tigers hidden by their stripes often hide in tall grass. restrictive/nonrestrictive
Many historical accounts told by the winners are not completely accurate. restrictive/nonrestrictive
My laptop running on its battery won't last much longer. restrictive/nonrestrictive
The fire extinguisher hanging by the back door is there in case the kitchen stove catches fire. restrictive/nonrestrictive
The trees surrounding the memorial were planted in the veterans' honor. restrictive/nonrestrictive
The zebras demonstrating their camouflage seemed to disappear behind the tall grasses. restrictive/nonrestrictive
The Dark is Rising written by one of my favorite authors is at the top of my pile of books to read. restrictive/nonrestrictive
The apples grown in that orchard are grown without pesticides. restrictive/nonrestrictive
This vase purchased at a flea market turned out to be worth a lot of money. restrictive/nonrestrictive